arch/x86/ebda: Change memcpy() to endian wrappers

Change memcpy()s and memset()s to endian.h wrappers for consistency
and safety. Add zero_n() wrapper to safely clear memory.

Change-Id: If155d82608c81992f05eae4d2223de6f506e98c5
Signed-off-by: Ryan Salsamendi <rsalsamendi@hotmail.com>
Reviewed-on: https://review.coreboot.org/20240
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/commonlib/include/commonlib/endian.h

@@ -18,6 +18,7 @@
 
 #include <stddef.h>
 #include <stdint.h>
+#include <string.h>
 
 /* Endian agnostic functions working on single byte. */
 
@@ -254,4 +255,9 @@ static inline void write_at_le64(void *dest, uint64_t val, size_t offset)
 	write_le64(d, val);
 }
 
+static inline void zero_n(void *dest, size_t n)
+{
+	memset(dest, 0, n);
+}
+
 #endif